1. Field of the Invention
The present invention relates to a die bonder and a bonding method, and particularly to a die bonder and a bonding method with a high operation ratio.
2. Description of the Related Art
As a part of steps of mounting a die (semiconductor chip) (hereinafter, simply referred to as a die) on a substrate such as a printed circuit board or a lead frame to assemble a package, a step of dividing a semiconductor wafer (hereinafter, simply referred to as a wafer) into dies and a bonding step of mounting the divided dies on the substrate are provided.
In the bonding step, the dies divided from the wafer are peeled off one-by-one from a dicing tape to be bonded on the substrate using an absorption jig that is referred to as a collet.
In such a die bonder, it is necessary to replace the collet in accordance with the type (die size), or to increase the frequency of replacement of the collet in contact with the surface of the die to prevent damage or taint of the surface of the die.
As conventional techniques of replacing the collet, for example, there are those described in Japanese Patent Application Laid-Open No. H4-321243 and Japanese Patent Application Laid-Open No. 2001-156083 are known. In Japanese Patent Application Laid-Open No. H4-321243, a collet clamper that holds a collet and a spring that operates the collet clamper are provided at the tip end of a bonding head to mechanically control the operation. Thus, the collet is replaced using a collet holder (a stock unit for collets for replacement, and corresponding to a supplying unit and a discarding unit of the application). On the other hand, in Japanese Patent Application Laid-Open No. 2001-156083, a collet attached to the tip end of a collet shank is inserted from the side to a port in a U-groove shape, and the collet is removed from the collet shank. Then, the collet shank is inserted into plural collets for replacement disposed on a plane, and is attached thereto. Further, Japanese Patent Application Laid-Open No. 2001-156083 discloses that the attachment of the collet is confirmed on the basis of the descent distance of the collet shank or optical means.
However, in the technique disclosed in Japanese Patent Application Laid-Open No. H4-321243, the mechanism of the tip end of the collet clamper is disadvantageously complicated. On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 2001-156083, an inserting space and a replacement area for collets for replacement become disadvantageously wide. Further, a die package has recently become thinner and the following problems occur. First, since a collet holder to hold a collet that stably absorbs the thinner die is used, it is necessary to replace only the collet while leaving the collet holder. Second, when confirming the attachment of the collet, it is necessary to move the collet to another installation position such as an alignment stage in a method using the descent distance of the collet shank, and the attachment cannot be promptly confirmed at the time of replacement. In addition, new optical means needs to be provided, or it is necessary to move to an area where another optical means is provided. Third, variations in the height of the collet at the time of manufacturing in a unit of nm have an impact on the descent distance of the collet when mounting the die, and it is necessary to address this problem.
Accordingly, an object of the present invention is to provide a bonding device and a bonding method with a high operation ratio by solving at least one of the above-described problems.